AT&T was one of three giants sharing some details about the inner workings of their networks this morning at the Open Network Summit in Silicon Valley.
While the other two – Google and Microsoft – build their data center networks to support online services like Google Search and Bing and provide cloud application and infrastructure services, such as Office 365, Azure, and Google Cloud Platform, a lot of of AT&T’s engineering muscle is used to support things like its gigabit internet access for consumers and businesses and its massive mobile-network user base.
To keep up with growth of the user base and its service portfolio as well as rising connectivity speeds, the company last year changed its approach to network architecture from buying off-the-shelf gear from incumbent vendors like Cisco, Alcatel-Lucent, or Ericsson, to using low-cost “commodity” hardware and relying on software to manage the increasingly complex set of functions the network has to perform.
This is the approach to network scale and complexity internet giants like Google, Microsoft and Facebook have taken. Like them, telcos operate networks that span the globe, but telcos have also been adding cloud services that are similar to those Google and Microsoft provide to their portfolios to leverage their network assets.
Open Source Network Hardware and Software
As it builds the new systems that support its services in its data centers and central offices around the world, AT&T relies a lot on open source software. In the process, however, it has also designed a lot of its own software and developed specifications for custom hardware underneath.
Today, the company announced it will contribute some of those network hardware specs to the Open Compute Project, a Facebook-led open source hardware and data center design initiative. It will also open source a series of network software tools it has developed through open source network technology communities.
When the hardware specs become open source, any hardware maker can come to AT&T with an offer to supply the boxes. Any other telco can also use those open specs and open source software to build their own data center network infrastructure in a similar fashion.
Replacing Complex Appliances With Software
AT&T’s gigabit home and enterprise internet service is called GigaPower. It’s extremely fast, but to provide that speed before the company had to install complex, expensive equipment in its central offices to provide it to neighborhoods – devices like gigabit passive optical network open line terminals, or GPON OLTs, for example, John Donovan, SVP of technology and operations at AT&T, wrote in a blog post.
Using Network Function Virtualization, the company’s engineers plan to replace those appliances with software running on commodity servers and other hardware.
Instead of simply replacing physical appliances with virtual ones, the team broke out and upgraded and optimized each subsystem on those devices. AT&T has done this with GPON OLTs, broadband network gateways, and Ethernet aggregation switches.
Several individual line cards in each OLT are virtualized and run on a single media access control (MAC) card. This vOLT (virtual OLT) is the piece of hardware AT&T is open sourcing through Open Compute.
“We’re inviting any white box hardware maker to build and sell them to us and also allowing others to build on the concept and design,” Donovan wrote. His team hopes to see prototypes by the end of the year and start trials and deployments in 2016.
An Open Source Broadband Access System
AT&T engineers are working with On.Lab, a non-profit open source network research foundation, to release an open source version of the software that enables vOLT called CORD, which is short for Central Office Re-architected as Datacenter. Together, vOLT and CORD will constitute a complete open source system to enable broadband access like AT&T’s GigaPower.
The company is also planning to open source a tool it uses to configure devices in its software-defined network through the OpenDaylight, an open source SDN project under the Linux Foundation.